From: matz@... (Yukihiro Matsumoto)
Date: 2001-12-28T16:42:50+09:00
Subject: [ruby-talk:29517] Re: C extensions: ruby and C strings

Hi,

In message "[ruby-talk:29515] C extensions: ruby and C strings"
    on 01/12/28, Tomasz Wegrzanowski <taw@users.sf.net> writes:

|1) Should I free string here or is it used as string buffer by Ruby ?
|	
|	char *cstr;
|	VALUE rstr;
|
|	rstr = rb_str_new2(cstr);
|	free (cstr); // ???

rb_str_new2() copies c string, so that you have to free cstr.

|2) Does cstr point to Ruby string buffer or should I free it ?
|
|	VALUE rstr;
|	char *cstr;
|
|	cstr = rb_str2cstr (rstr, 0);
|	do_something_with_const_string (cstr);
|	free (cstr); // ???

In this case, cstr is a pointer to a internal buffer in a String
object, so that you don't have to free.

|3) Is RSTRING(rstr)->ptr null-terminated ?

Yes.  But do not rely on it too much.  I'd like to guarantee that a
pointer retrieved from rb_str2cstr() (or StringValuePtr() in 1.7) is
null-terminated.

							matz.